This invention relates to a chopped fiberglass trilaminate structure and a method of manufacture, and more particularly to a chopped fiberglass laminate having improved elongation for use in forming moldable headliners made from such structures for motor vehicles.
Prior art constructions of moldable headliners for trucks and automotive vehicles generally included a phenolic saturated fiberglass mat molded into a shell. In a secondary step, a cloth decorative outer layer, usually of a nylon tricot fabric backed with a 3 mm foam layer is attached to the shell. The foam helps to hide imperfections in the fiberglass shell.
The automotive industry recently has moved away from this construction to accepted European technology. This technology involves use of a multi-layered composite including a foam core and two outer layers of chopped fiberglass surrounding the foam core. The fiberglass is either chopped in place or provided in mat form and generally includes fiberglass yarns in tow form cut to about 1.27 to 10.16 cm (xc2xdxe2x80x3 to 4xe2x80x3) long. This tri-laminate is saturated with an isocyanate resin which bonds the layers together during the molding process which forms the part into a shape to fit into a specific vehicle. The fiberglass layers on either side of the foam core are included to impart proper stiffness to the headliner part.
The European triplex construction is generally further sandwiched between outer film layers. These film layers act as barriers to prevent the liquid isocyanate resin from penetrating through the top layer which is the decorative fabric. Similarly, the film layer on the back of the part prevents the isocyanate from penetrating the backing mold release layer and contaminating the mold. If the liquid adhesive bleeds through the decorative fabric, it would be visible and a cause for rejection of the part, or it could cause sticking or attachment of the back side of the part to the mold.
There are ongoing efforts in the automotive industry to provide moldable headliner components which exhibit increased elongation in both the machine and transverse directions and to facilitate fabrication into severe curves and offsets during the curing process. Conventional glass fiber layers added to improve stiffening of the finished headliner generally are brittle thereby limiting the ultimate shape of the finished product.
One example of a commercial sound absorbing laminate is shown in U.S. Pat. No. 4,828,910 to Haussling. Here the laminate structure includes a reinforcing porous mat of chopped glass fiber integrally bonded to a resilient fibrous batt. A decorative cover sheet covers the exposed or exterior surface of the reinforcing mat all bonded together by a thermoset resin binder. The reinforcing mats sandwiching the fibrous batt are of glass fibers bonded together by a thermoformable resin to impart the required stiffness to the finished headliner. Finally, a porous cloth scrim as a release layer is adhesively secured to the back of the reinforcing mat by the thermoset resin coating the mat.
Another type of molded automobile headliner is shown in U.S. Pat. No. 4,840,832 to Weinle, et al. Here, the headliner is formed from a batt of polymeric fibers including at least a portion of potentially adhesive fibers. The finished headliner is characterized by being of a highly deformable resilient construction which facilitates installation in the vehicle. The fibers in the batt are bonded together at a multiplicity of locations which impart a self-supporting molded rigidity allowing the headliner to retain its shape when installed. A flexible foam layer is adhered to one surface of the flexible batt and the outer textile fabric is bonded to the foam layer.
Romesberg, et al. in U.S. Pat. No. 5,486,256 and 5,582,906 disclose a typical foam core I-beam type headliner having a layer of chopped fiberglass on both sides of a central foam core. The chopped fiberglass is applied at a first glass chopping stations onto a belt of adhesive film which becomes the back fiberglass layer and deposits a second fiberglass layer onto the front of the foam layer at a second glass chopping station. A wet adhesive is then applied onto the second fiberglass layer and a decorative fabric applied to the adhesive prior to molding.
U.S. Pat. No. 5,591,289 to Souders, et al describes another headliner based on a fibrous batt including binder fibers coated with a thermoset resin for imparting stiffness to the part. In U.S. Pat. No. 5,660,908 to Kelman, et al. A 100% polyethylene terephthalate (PET) headliner is formed from a fibrous batt having a plurality of impressions which are filled with PET filler and bonded to a PET scrim for imparting additional stiffness.
While the available constructions produce suitable composites, constructions that include glass fibers for stiffening the final product remain difficult to mold. Accordingly, it is desirable to provide a chopped fiberglass laminate for a moldable headliner which will provide a composite for molding having at least about 30 percent elongation in both the machine and transverse directions, allow excellent conforming to deep-draw areas when molding and provide the required stiffness in the final headliner product.
Generally speaking, in accordance with the invention, a chopped fiberglass laminate for fabricating moldable structures and methods of fabrication of the laminate and headliner including the laminate are provided. The chopped fiberglass laminate is formed by feeding a continuous nonwoven scrim of fine denier synthetic fiber and a non-porous barrier film through nip rollers. Chopped fiberglass and adhesive are deposited on the moving barrier film and nonwoven scrim which is then heated in an oven, passed through pressure nip rollers, cooled and then wound in roll form for transport and use.
The chopped fiberglass laminate possesses elongation properties at break exceeding about 30 to 40% in both the machine and transverse directions. The fine denier synthetic fiber utilized in the nonwoven scrim is a spunbond fiber having a denier of between about 1.8 to 2.2 in order to impart the desired elongation properties.
A headliner composite is formed by combining the fiberglass laminate with a foam layer on the fiberglass surface, an additional fiberglass layer is disposed on the opposite surface of the foam and a decorative fabric which may include a foam backing is placed on the exposed fiberglass surface. This headliner composite is then ready for molding. The high elongation properties of the chopped fiberglass laminate provide excellent conformability to deep-draw areas in the mold.
Accordingly, it is an object of the invention to provide a scrim/barrier film/chopped fiberglass containing laminate structure having improved elongation properties.
Another object of the invention is to provide an improved chopped fiberglass containing laminate including a nonwoven scrim formed of fine denier spunbond synthetic fibers.
A further object of the invention is to provide an improved chopped fiberglass containing laminate including a nonwoven scrim formed of fine denier spunbond polyester fibers of about 1.8 to 2.2 denier.
Yet another object of the invention is to provide an improved chopped fiberglass containing laminate including a thermoplastic barrier film for adhering the chopped fiberglass thereto and providing a non-porous barrier to prevent mold contamination.
Yet a further object of the invention is to provide a method for fabricating a chopped fiberglass containing laminate with elongation at break exceeding 30 to 40% in both the machine and transverse directions and energy to break less than 20 lbf-in. in either direction.
Still a further object of the invention is to provide a method for forming the nonwoven scrim/barrier film/chopped fiberglass laminate which can be formed into a roll or sheeted for easy storage and transport prior to being combined to form an automotive headliner composite.
Still another object of the invention is to provide an apparatus for forming a nonwoven scrim/barrier film/chopped fiberglass laminate which can be stored in roll or sheet form.
Still other objects and advantages of the invention all or in part be obvious and all in part be apparent from the specification.
The invention accordingly comprises several steps and the relation of one or more of such steps with respect to each of the others, and the products which possess the characteristics, properties and relation of constituents (components), all as exemplified in the detailed disclosure hereinafter said forth, and the scope of the invention will be indicated in the claims.